 ```ts
/**
 * Splits an array into consecutive groups of at most size elements, preserving order.
 * @param items - The array to be chunked. Must not be mutated.
 * @param size - The maximum number of elements per group. Must be a positive integer.
 * @returns An array of arrays, each containing up to `size` elements from the input array.
 */
export function chunk<T>(items: readonly T[], size: number): T[][] {
    if (!Number.isInteger(size) || size <= 0) {
        throw new Error("Size must be a positive integer");
    }

    const result: T[][] = [];
    for (let i = 0; i < items.length; i += size) {
        result.push(items.slice(i, i + size));
    }

    return result;
}
```